MICROANATOMY

Detailed explanation-1: -21.4 Sarcoplasmic Reticulum and its Couplings to the Plasma Membrane. Each myofibril within the cell is surrounded by a network of interconnecting membranous tubules and cisternae, the SR (Figs.

Detailed explanation-2: -The sarcoplasmic reticulum is a complex network of specialized smooth endoplasmic reticulum that is important in transmitting the electrical impulse as well as in the storage of calcium ions. These longitudinal tubules form a membrane-bound system of tubules and cisterns that surround the myocytes.

Detailed explanation-3: -In heart muscle cells, most of the calcium is stored inside a chamber named the sarcoplasmic reticulum. The calcium in the sarcoplasmic reticulum is released during heart muscle contraction and transported back inside the sarcoplasmic reticulum during relaxation.

Detailed explanation-4: -The SR is composed of tubules and cisternae surrounding each myofibril.

Detailed explanation-5: -The Sarcoplasmic Reticulum: Storage and Release of Calcium.